The US military is planning for a potential sustained campaign against Iran should President Donald Trump order an attack, two senior US officials told Reuters.

The officials, who spoke on the condition of anonymity, emphasised that the move could trigger a significant Iranian retaliation, risking a prolonged regional conflict which could be far more serious than previous confrontations.

They added, without providing detail, that US strikes would not just target nuclear infrastructure, but also Iranian state and security facilities. US attacks on the country last year primarily targeted nuclear sites.